Summary

In this book various methods for extending the bandwidth of telephone bandlimited speech signals have been presented, discussed and evaluated. Focus of the book was laid on the problems that arise from dealing with realworld signals. The required basic methods for speech analysis and synthesis have been recapitulated as well as the extraction of different speech features and adequate distance measures including an improved distance measure for a terminal evaluation have been presented. The approaches for extending the bandwidth of a speech signal have been split into the generation of an extended excitation signal and the extension of a spectral envelope following the source-filter model for the speech production process. These parts have been discussed and evaluated separately.